The undesirable formation of large cavities or pockets in a foam structure. Voids are usually caused by poor moldability or incorrect mold filling. In the case of foam buns, voids occur when then blowing and polymerization reactions are out of balance.

(1) In a solid plastic, an unfilled space of such size that it scatters radiant energy such as light. (2) A cavity unintentionally formed in a cellular material and substantially larger than the individual cells.

(1) Holes on the outside of the pipe in the surrounding soil or material. (2) A term generally applied to paints to describe holidays, holes, and skips in the film. Also used to describe shrinkage in castings or welds.

White spots in areas of electrostatic output that should have colour. Commonly the result of airborne particles preventing the charged toner from adhering to the charged paper. Can also result from dirt in paper.

A letting void is any period when the property is not subject to tenancy and therefore the landlord is not receiving any rental income. During any such periods not only is the landlord not receiving an income but also his costs will increase. In addition to insurance and mortgage payments that he may have to make, he may incur costs in respect to connected utilities and will be responsible for Council Tax and Leasehold Ground Rent and Maintenance charges. There are two void periods that an investor must take into account: The period between completion of the purchase of the property and the first tenant moving in. Given the time taken to re-fit the property for tenancy, a period of 3 to 4 weeks should be allowed. The period between a present tenant moving out and a new tenant moving in. Typically, the industry allows a period of 4 weeks per year.